BMW E87 E90 LCI 120i 320i Rear Differential Diff 3,45 Ratio 7524321 WARRANTY

BMW E87 E90 LCI 120i 320i Rear Differential Diff 3,45 Ratio with a 3.45 ratio is an original drivetrain component, specifically designed for the rear axle of these models. Thanks to its factory BMW design, it ensures proper torque transfer, stable handling, and predictable vehicle behavior during daily operation. This is the solution for users who want to restore the stock performance of their drivetrain without experimenting with unreliable replacements.

Specifications and technical data

• SKU: 7524321
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7524322
• Substitutable numbers: 33107524322, 7524322, 33107524321, 7524321
• Location on the vehicle: Rear
• Category: Additional Differential Parts

Purpose and function in the drivetrain

The presented rear differential is dedicated to the Rear axle in selected versions of the BMW 1 Series E87 and 3 Series E90 LCI with 120i and 320i petrol engines. It is responsible for distributing power to the rear wheels, providing the correct gear ratio, and ensuring the stable operation of the entire drive axle, which translates into predictable acceleration, smooth load changes, and proper integration with the vehicle's electronics.

The factory 3.45 ratio was selected by BMW engineers to provide a balance between dynamics and fuel economy. Using an original differential with this ratio allows you to maintain the stock characteristics of the gearbox and engine, without the risk of unwanted changes in the car's behavior.

Construction, compatibility, and OEM advantages

As an item from the Other differential parts group, this drive axle is an OEM BMW construction, which means it maintains factory manufacturing tolerances, mounting geometry, and operating parameters. As a result:

• it fits the stock mounting points on the chassis without any modifications,
• it works with original half-shafts and the driveshaft,
• it maintains the correct drivetrain alignment and rear suspension geometry.

An original BMW differential minimizes the risk of noise, vibration, or leakage issues that often occur with imprecisely manufactured replacements. This is particularly important in vehicles where handling stability and predictable rear axle behavior are a priority.

Condition, verification, and service application

The component comes from a used vehicle, which allows for an economical repair of the drivetrain while maintaining original BMW quality. This type of differential is highly recommended in situations where the current drive axle shows signs of wear, such as increasing noise, whining under load, or noticeable play in the drivetrain.

In workshop practice, using a complete, used OEM differential often shortens repair time compared to rebuilding an old unit, while simultaneously allowing for the maintenance of the structural integrity of the entire system. This solution is frequently chosen by both professional service centers and conscious users who prioritize factory-fit components.

Part selection and technical support

To correctly match this differential to a specific BMW vehicle, it is worth verifying compatibility with the VIN and the vehicle's drivetrain configuration. The product has a dedicated OEM part number and associated interchangeable numbers, which facilitates clear identification in service catalogs and parts selection systems.

If you are planning a comprehensive repair or upgrade of the drivetrain area in your BMW and need other components from the same group, such as housings, mounts, or additional axle sub-assemblies, check out the available parts in the Other BMW differential parts category.

More about used BMW differentials

For symptoms such as whining, humming, or jerking during acceleration, it is worth considering replacing the entire drive axle with a verified OEM component from the secondary market. A detailed discussion of the advantages of this solution, the differences between used original components and unreliable replacements, as well as practical service tips can be found in the article: Whining differential? Find out why a used OEM drive axle is a better investment than an unreliable replacement.